The conspiracy theorist in me thinks:
1. NYR FO doesn't think Kostka is good enough to be a 7D in the NHL
2. NYR FO and coaching staff believe Hunwick is capable of playing a top-6 role every night
3. NYR FO will be trading John Moore when McDonagh is healthy
4. Because of 3, NYR need a 7D on the roster.
Methinks you are right!
All depends on who they acquire of course. If they get another DMan via trade, then this isn't needed.
The Rangers got to see what their defensive "depth" has to offer and its not a marginal playoff team, let alone contender.
See I look at each game this season that Moore's played and I don't see improvement. I see the good that's in his game, but I still see mistakes he's making. Basically he's been the same player since he was traded for.
The team has had success with him in the line up, but in a sheltered role.
A team that can ice a full 6 d without any sheltering is a D that is stacked.
No holes.
Kostka presents a big, gaping giant hole.
Hunwick was solid for stretches, and then its like wtf man bad for stretches. Moronic play.
Allen takes a lot of uncessary risks, bad positioning on rushes. McIlrath does too much.
So yeah your post has a lot of merit.